基于机构组合原理复杂机构的符号表达

概念产品的信息表达是目前实现计算机对机构概念设计支持的瓶颈问题，作者基于机构组合原理，用矩阵形式描述基本机构，给出了串联式、并联式和混合式3种基本机构的组合方式的符号表达方法，该方法能够描述机构的类型、连接关系、空间位置关系以及机构的多功能等信息，为开发基于基本机构组合的复杂机械系统的计算机辅助概念设计系统奠定了理论基础，以复杂凸轮连杆机构为例，验证了本文提出的符号表达方法的可行性。     

机构的构型及优化设计

运用机构的不同组合原理和方法，优化选择机构的类型，借助计算机编程、解析计算，对机械中的机构运动进行分析、综合、优化，得出精确的设计结果，为有特殊要求的机械设计服务。     

组合机构分类方法的探讨

通过对组合机构的组合原理和结构型式等进行分析和研究,本文给出了基本机构的定义、组合机构的定义,并对组合机构的组合原理和分类方法提出了自己的见解和看法。使机构组合理论更加清晰、易懂,有益于利用机构的组合理论进行机构创新设计。     

凸轮-槽轮组合机构及其设计

分析了槽轮机构运动时产生冲击的原因和影响因素 ,提出了用凸轮机构的摆动从动件作为槽轮机构的主动拔盘 ,从而构思了一种无啮合冲击的凸轮—槽轮组合机构 ;还对从动件运动规律的选择和设计注意事项进行了分析讨论     

用偏心齿轮连杆组合机构实现两行程等速运动

利用偏心齿轮机构既可以获得变传动比，又容易制造的特点，提出了将其与正弦机构组合在一起，从而实现从动件在往复两行程内作近似等速移动的设计思路．指出了实现此设计思想的关键是选择各机构的相对安装位置．最后通过算例予以验证．     

机构封闭组合与创新设计

串行连接和并行连接的基本机构是单自由度机构.根据机构的结构原理和组成原理,按其连接方式,提出了单自由度机构与多自由度机构的组合称为封闭式连接组合的观点,并用两自由度机构和单自由度机构的组合实例进行了说明和论证.所提出的封闭组合方法不但增强了机构组合方法的可操作性,而且有利于机构创新设计.     

计算机辅助运动分析与绘图

本文运用约束方程法对平面机构的运动提出了五种模块,并列出其数学模型。利用AUTOCAD提供的命令组文件的概念,用高级语言编制了能被AUTOCAD调用的绘图文件。最后以六杆机构,齿轮—连杆机构,凸轮—连杆机构为例,说明对平面机构的轨迹进行模块式组合设计与绘图的方法及计算机运算框图。     

汽车座椅上下调节机构数字化设计

基于功能要求确定以蜗杆凸轮组合机构作为汽车座椅上下调节机构的运动方案,基于机构学理论建立该组合机构设计数学模型并在Matlab软件中编程求解,在CATIA软件中建立该组合机构各零件参数化模型并进行虚拟装配,利用基于装配体的有限元分析技术在ANASYS软件中对该组合机构总成数字化模型进行了强刚度分析和评价．最后,给出了一个设计实例．     

多自由度并联机构组合弹性阻尼减振装置分析

首次采用多自由度并联机构作为基体辅以稀土永磁及浮动弹性阻尼系统，组合成多自由度弹性阻尼减振装置，较好地解决了多自由度的减振问题，以救护车用担架支架三维隔振装置为例分析为其隔振要求，采用三自由度并联机构组合弹性阻尼减振装置，介绍其结构及有关参数的设计方法，该方法的结果与动态模拟及实验结果一致，说明其分析方法是正确的，该方法可推广到其他要求多维减振的设备上。     

空间机构运动分析的正交螺旋法

本文用正交螺旋法对一个自由度单环空间机构的运动进行了分析,导出其速度、加速度的度算公式,并对输入构件为连杆和不同运动副的组合进行了讨论,最后以具有三平行轴的七杆空间机构为例作了数字计算。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-